Method for polymer-assisted chip transfer

ABSTRACT

One or more chips are transferred from one substrate to another by using one or more polymer layers to secure the one or more chips to an intermediate carrier substrate. While secured to the intermediate carrier substrate, the one or more chips may be transported or put through further processing or fabrication steps. To release the one or more chips, the adhesion strength of the one or more polymer layers is gradually reduced to minimize potential damage to the one or more chips.

TECHNICAL FIELD

The present disclosure relates to chip fabrication, and morespecifically to transferring chips from one substrate to another duringa fabrication process.

BACKGROUND

Semiconductor device fabrication often involve multiple steps that mayrequire that at least part of the device be strongly secured at times,such as to a substrate. For example, when transporting apartially-fabricated semiconductor device, it is desirable that thedevice to be secured to the substrate strongly enough so that it doesnot shift or become detached from the substrate. Similarly, it is alsodesirable for the device to be secured during certain fabricationprocesses. One such process is laser lift-off (LLO), which is used todetach semiconductor devices from a substrate they are chemicallyadhered to. During LLO, a laser is focused on the interface of asubstrate and base of the semiconductor device, often sapphire andgallium nitride, respectively. As the laser heats the interface, thebonds at the interface are broken, and the substrate can subsequently beremoved. However, the devices need to be kept in place during the LLOprocess to avoid damaging the devices.

LLO may be part of a larger “chip transfer” process through whichsemiconductor device chips are removed from one substrate and placedonto another. Adhesive tapes are conventionally used for chip transferprocesses and may be heat- or UV-release materials. However, such tapesare not suitable for ultra-fine-pitch interconnects (e.g., <10 μm pitch,<5 μm diameter, <5 μm height). Adhesive tapes are only able to provide asingle level of adhesion, which is often too strong and preventsreliable chip release. Smaller devices especially may be damaged uponremoval when the adhesion strength is too high. Alternatively, if theadhesion strength is too low, the devices may be disrupted duringtransportation or processing (such as LLO). Furthermore, adhesive tapesare highly flexible, which can cause chip misalignment during and afterthe transfer process.

SUMMARY

One or more chips are transferred from one substrate to another by usingone or more adhesive layers to secure the one or more chips to anintermediate carrier substrate. While secured to the intermediatecarrier substrate, the one or more chips may be transported or putthrough further processing or fabrication steps. To release the one ormore chips, the adhesion strength of the one or more polymer layers isgradually reduced to minimize potential damage to the one or more chips.

In one embodiment, one or more chips are secured to a first substrate bydepositing a first adhesive layer on the first substrate, depositing asecond adhesive layer that is made of a different material than thefirst adhesive layer on the first substrate, and placing one or morechips on the first substrate through the first and second adhesivelayers. The one or more chips are detached from the first substrate byremoving the second adhesive layer from the first substrate, softeningthe first adhesive layer, and removing the one or more chips from thefirst substrate.

In another embodiment, one or more chips are secured to a firstsubstrate by depositing a polymer layer on the first substrate, andplacing one or more chips on the first substrate through the polymerlayer, such that one or more portions of the polymer layer coveringedges of the one or more chips. The polymer layer is then dried, such asby evaporation. The one or more chips are detached from the firstsubstrate by removing the one or more portions of the polymer layer fromthe edges of the one or more chips, softening one or more remainingportions of the polymer layer, and removing the one or more chips fromthe first substrate.

In yet another embodiment, one or more chips are secured to a firstsubstrate by depositing a first adhesive layer on the first substrate,placing one or more chips on the first substrate through the firstadhesive layer, and depositing a second adhesive layer on the firstsubstrate. The second adhesive layer is made of a different materialthan the first adhesive layer and comes into contact with a secondsubstrate the one or more chips are attached to. The second adhesivelayer covers edges of second substrate and some edges of the one or morechips but does not cover other portions of the one or more chips. Theone or more chips are detached from the first substrate by removing thesecond adhesive layer from the first substrate, softening the firstadhesive layer, and removing the one or more chips from the firstsubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary implementations of the present disclosure are described hereinwith reference to the accompanying drawings, in which:

Figure (FIG. 1 shows a cross-sectional view of a chip secured to acarrier substrate via a double adhesive layer, according to oneembodiment.

FIG. 2A is a flow chart of a method for attaching the chip to thecarrier substrate via a double adhesive layer, according to oneembodiment.

FIG. 2B is a flow chart of a method for releasing the chip that isattached to the carrier substrate via a double adhesive layer, accordingto one embodiment.

FIG. 3 is a cross-sectional view of the chip secured to the carriersubstrate via a single polymer layer, according to one embodiment.

FIG. 4A is a flow chart of a method for securing the chip to the carriersubstrate via a single polymer layer, according to one embodiment.

FIG. 4B is a flow chart of a method for releasing the chip that isattached to the carrier substrate via the single polymer layer,according to one embodiment.

FIG. 5 shows a cross-sectional view of the chip secured to a carriersubstrate via an edge double adhesive layer, according to oneembodiment.

FIG. 6A is a flow chart of a method for securing the chip to the carriersubstrate via an edge double adhesive layer, according to oneembodiment.

FIG. 6B is a flow chart of a method for releasing a chip that isattached to a carrier substrate via an edge double adhesive layer,according to one embodiment.

The figures depict various embodiments of the present invention forpurposes of illustration only. One skilled in the art will readilyrecognize from the following discussion that alternative embodiments ofthe structures and methods illustrated herein may be employed withoutdeparting from the principles of the invention described herein.

DETAILED DESCRIPTION

Generally disclosed herein are methods for transferring chips from onesubstrate to another using one or more adhesive layers to secure a chipto a surface of the substrate and reduce the adhesion strength of theone or more adhesive layers when removing the chip from the surface. Bydoing this, the disclosed transfer methods are better able to secure thechip to the surface strongly enough for transportation and processessuch as LLO, while also limiting damage of the chip upon removal fromthe surface.

Herein, a “chip” refers to a semiconductor device such as, but notlimited to, a micro-light-emitting diode (microLED). In one embodiment,the chip is specifically a gallium nitride (GaN) microLED.

The chip transfer methods are explained below for a single example chipbeing transferred from a “fabrication substrate” to a “target substrate”via a “carrier substrate.” The fabrication substrate is a substrate thatthe chip is attached to before it is transferred, such as a substratethe chip was fabricated on. Example fabrication substrates includesapphire and silicon. The target substrate is a substrate the chip isplaced on after it is transferred. For example, the chip may be placedon a target substrate where it is part of a larger device, such as amicroLED array. The carrier substrate is a hard material, which reducesthe planar flexibility of the adhesive layer(s) used to adhere the chipto the carrier substrate. Thus, the combination of the hard carriersubstrate and the adhesive layer(s) form a rigid adhesive surface.Example carrier substrates include glass and silicon. The fabricationand/or target substrates may not be involved in some embodiments of thedisclosed methods. For example, one or more chips may have already beenremoved from their fabrication substrate and before being secured to thecarrier substrate.

The adhesive materials discussed in conjunction with the disclosedmethods include waxes, such as carnauba wax and bees wax, and polymermaterials. The following polymer materials are specifically discussed:polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), polyvinyl pyrrolidone(PVP), and polyvinyl butyral (PVB). However, these adhesive materialsare merely examples, as many different adhesive materials that meet therequirements described may be used in these methods. For example, theadhesive materials need not be limited to waxes and vinyl polymers.

Reference will now be made in detail to several embodiments, examples ofwhich are illustrated in the accompanying figures. It is noted thatwherever practicable similar or like reference numbers may be used inthe figures and may indicate similar or like functionality. The figuresdepict embodiments of the disclosed system (or method) for purposes ofillustration only. One skilled in the art will readily recognize fromthe following description that alternative embodiments of the structuresand methods illustrated herein may be employed without departing fromthe principles described herein.

Double Adhesive Layer System

FIGS. 1, 2A, and 2B illustrate a double adhesive layer chip transfersystem, according to one embodiment. FIG. 1 shows a cross-sectional view100 of the chip 110 (on a fabrication substrate 120) secured to acarrier substrate 130 via a double adhesive layer, according to oneembodiment. A first adhesive layer 140 is on the surface of the carriersubstrate 130, while a second adhesive layer 150 is on top of thesurface of the first adhesive layer 140. The adhesion strength of thedouble adhesive layer system can be controlled by the thicknesses of theadhesive layers 140 and 150. For example, the first adhesive layer 140may be thinner than the second adhesive layer 150, as shown in FIG. 1.Adhesive layer thicknesses are further discussed in conjunction withFIG. 2A.

FIG. 2A is a flow chart of a method 200 for attaching the chip 110 tothe carrier substrate 130 via a double adhesive layer, according to oneembodiment. The first adhesive layer 140 is deposited 202 onto thecarrier substrate 130 and the second adhesive layer 150 is depositedonto the first adhesive layer 140. The adhesive layers 140 and 150 maybe deposited 202 and 204 using standard thin film deposition techniques,such as spin-coating and dip-coating.

The first and second adhesive layers 140 and 150 are made of adhesivematerials with different properties that allow them to be removedseparately. Specifically, the first and second materials are soluble indifferent solvents and/or able to be dry etched by different chemicalspecies. For example, the first material (of the first adhesive layer140) is soluble in a first solvent in which the second material (of thesecond adhesive layer 150) is insoluble, and the second material may besoluble in a second solvent in which the first material is insoluble. Atleast one of the first and second materials is a polymer material. Theother of the first and second materials may be a wax, such as carnaubaor bees wax, or another polymer material. In one embodiment, the firstmaterial is a polymer material and the second material is a wax.Specifically, the second material may be carnauba wax. In anotherembodiment, the first material is PVAc and the second material is PVA.In yet another embodiment, the first material is PVP and the secondmaterial is PVB. Additionally or alternatively, the first and secondmaterials have different glass transition temperatures, which allows theadhesion properties of the first and second adhesive layers 140 and 150to be modified individually.

The first and second adhesive layers 140 and 150 may be of differentthicknesses, so as to control the total level of adhesion and thereduced level of adhesion after the second adhesive layer 150 isremoved. In one embodiment, the first adhesive layer 140 isapproximately 1 micrometer thick, and the second adhesive layer 150 is2-3 micrometers thick.

In some embodiments, the adhesive layers 140 and 150 are dried 206, suchas by evaporation, an electron beam, UV radiation, heat, or chemicaldrying agents.

The carrier substrate 130 is heated 208 to soften the adhesive layers140 and 150 in preparation for chip placement 210. The temperature forsoftening the adhesive layers 140 and 150 is dependent on the type ofadhesive material being used. Typically, the temperature that thecarrier substrate 130 is heated 208 at least to the glass transitiontemperatures of the adhesive layers 140 and 150. For example, thecarrier substrate 130 is heated to at least 85° C. if the adhesivelayers 140 and 150 are PVAc and PVA, and the carrier substrate 130 isheated to at least 110-180° C. if the adhesive layers are PVP and PVB.

The chip 110 is weighted (e.g., with a few grams) and placed 210 on theheated carrier substrate 130, through the second adhesive layer 150 andthe first adhesive layer 140. The chip 110 is fully secured to thecarrier substrate 130 once the temperature returned to below the glasstransition temperature of one or both of the adhesive materials, fixingthe chip 110 in place and increasing the level of adhesion.

FIG. 2B is a flow chart of a method 250 for releasing the chip 110 thatis attached to the carrier substrate 130 via a double adhesive layer(made of adhesive layers 140 and 150), according to one embodiment.Method 250 includes optional processing steps (indicated in dottedlines) through which the fabrication substrate 120 can be removed. Theseare an example of what processing may require a stronger level ofadhesion. Alternatively or additionally, the carrier substrate 130 maybe used to secure the chip 110 for transport or shipping.

While the chip 110 is strongly adhered to the carrier substrate 130, thefabrication substrate 120 may be removed by performing 252 laserlift-off or a similar process to break any physical and/or chemicalbonds between the chip 110 and the fabrication substrate 120. Once thosebonds are broken, the fabrication substrate 120 can be physicallyremoved 254 from the chip 110. The fabrication substrate 120 may beheated to aid in its removal 254. For example, a sapphire fabricationsubstrate 120 is heated to 30° C. prior to removal 254.

After the fabrication substrate 120 has been removed 254, the level ofadhesion between the chip 110 and the carrier substrate 130 is decreasedby removing 256 second adhesive layer 150 from the carrier substrate 130and the chip 110. The chip 110 remains adhered to the carrier substrate130 via the first adhesive layer 140. In one embodiment, the secondadhesive layer 150 is removed 254 by the rinsing carrier substrate 130with a solvent in which the second adhesive layer 150 is soluble but thefirst adhesive layer 140 is not. Example solvents include water,butanone, ethanol, and isopropanol. Specifically, the carrier substrate130 is rinsed with water if the second adhesive layer 150 is PVA (andthe first adhesive layer 140 is not PVP), with butanone if the secondadhesive layer 150 is PVAc, with water (if the first adhesive layer 140is not PVA) or isopropanol if the second adhesive layer 150 is PVP, andthe carrier substrate 130 is rinsed with ethanol if the second adhesivelayer 150 is PVB.

The carrier substrate 130 is heated 258 to soften the first adhesivelater 140 so that the chip 110 can be removed 260 from the carriersubstrate 260 (e.g., so it can be placed on a target substrate). Again,the temperature that the carrier substrate 130 is heated to depends onthe adhesive material being used. For example, the carrier substrate 130is heated to at least 45° C. when the first adhesive layer 140 is PVAc,or to at least 110-180° C. when the first adhesive layer 140 is PVP.Alternatively or additionally, the first adhesive layer 140 can be dryetched to reduce its adhesion strength before removing 260 the chip 110from the carrier substrate 130.

Single Polymer Layer System

FIGS. 3, 4A, and 4B illustrate a single polymer layer chip transfersystem. FIG. 3 shows a cross-sectional view 300 of the chip 110 (on thefabrication substrate 120) secured to the carrier substrate 130 via asingle polymer layer 340, according to one embodiment. The singlepolymer layer 340 is on the surface of the carrier substrate 130 and mayalso come into contact with the fabrication substrate 120. In thisembodiment, adhesion strength is controlled by the amount of the polymerlayer 340 that is removed 454, which is discussed in conjunction withFIG. 4B.

FIG. 4A is a flow chart of a method 400 for securing the chip 110 to thecarrier substrate 130 via a single polymer layer 340, according to oneembodiment. The carrier substrate 130 is prepared by depositing 402 thesingle polymer layer 340 on the carrier substrate 130. The polymer layer340 may be deposited 202 using standard thin film deposition techniques,such as spin-coating and dip-coating.

The polymer layer 340 is made of a polymer material that is able to beselectively removed by a laser, which is further described inconjunction with FIG. 4B. Examples of possible polymer materials includePVAc, PVA, PVP, and PVB. The thickness of the polymer layer 340 is suchthat the chip 110 can be fully embedded in the polymer layer 340 withthe fabrication substrate 120 also coming into contact with the polymerlayer 340. For example, the thickness of the polymer layer 340 may beapproximately equal to or a little less than a height of the chip 110.

The chip 110 is placed 404 on the carrier substrate 130, through thepolymer layer 340. After placement 404, the sides of the chip 110contact the polymer layer 340. The sides of any morphology on the bottomof the chip 110, such as ridges or prongs, also comes into contact withthe polymer layer 340.

In some embodiments, the polymer layer 340 is dried 406, such as byevaporation, an electron beam, UV radiation, heat, or chemical dryingagents, before or after chip 110 placement 404. If the polymer layer 340is dried before chip 110 placement 404, the carrier substrate 130 mayalso be heated (similarly to step 208 of method 200) before chip 110placement 404 in order to soften the polymer layer 340.

FIG. 4B is a flow chart of a method 450 for releasing the chip 110 thatis attached to the carrier substrate 130 via the single polymer layer340, according to one embodiment. Method 450 includes optionalprocessing steps (indicated in dotted lines) through which thefabrication substrate 120 can be removed. These are an example of whatprocessing steps may require a stronger level of adhesion. Alternativelyor additionally, the carrier substrate 130 may be used to secure thechip 110 for transport or shipping.

While the chip 110 is strongly adhered to the carrier substrate 130, thefabrication substrate 120 may be removed by performing 452 LLO or asimilar process to break any physical and/or chemical bonds between thechip 110 and the fabrication substrate 120.

To decrease the adhesion strength of the polymer layer 340, portions ofthe polymer layer 340 covering the edges of the chip 110 are removed 454from the carrier substrate 130. The portions of the polymer layer 340that are removed 454 include any portions of the polymer layer 340contacting the edges of the fabrication substrate 120. In someembodiments, portions of the polymer layer 340 contacting the undersideof the fabrication substrate 120 may not be removed 454. The removal 454may be performed via a laser, such as a carbon dioxide laser.

The removal 454 of portions of the polymer layer 340 dislodges thefabrication substrate 120 so that it can be removed 456 from the chip110. The fabrication substrate 120 may be heated to aid in its removal456. For example, a sapphire fabrication substrate 120 is heated to 30°C. prior to removal 456. In some embodiments, steps 454 and 456 may bereversed.

The carrier substrate 130 is heated 458 to soften the remaining portionsof the polymer later 340 so that the chip 110 can be removed 460 fromthe carrier substrate 130 (e.g., so it can be placed on a targetsubstrate). The temperature that the carrier substrate 130 is heated todepends on the polymer material being used. For example, the carriersubstrate 130 is heated to at least 85° C. when the polymer layer 340 isPVA, at least 45° C. when the polymer layer 340 is PVAc, to at least110-180° C. when the polymer layer 340 is PVP, or to at least 62-78° C.when the polymer layer 340 is PVB. Alternatively or additionally, thepolymer layer 340 can be dry etched to reduce its adhesion strengthbefore removing 460 the chip 110 from the carrier substrate 130.

Edge Double Adhesive Layer System

FIGS. 5, 6A, and 6B illustrate an edge double adhesive layer chiptransfer system, according to one embodiment. FIG. 5 is across-sectional view 500 of the chip 110 (on a fabrication substrate120) secured to a carrier substrate 130 via an edge double adhesivelayer, according to one embodiment. A base adhesive layer 540 is on thesurface of the carrier substrate 130. An edge adhesive layer 550 is theon the surface of the base adhesive layer 540, but only around the sidesand edges of the chip 110. The adhesion strength of the edge doubleadhesive layer system can be controlled by the thicknesses of theadhesive layers 540 and 550. For example, the base adhesive layer 540may be thinner than the edge adhesive layer 550, as shown in FIG. 5.Adhesive layer thicknesses are further discussed in conjunction withFIG. 6A.

FIG. 6A is a flow chart of a method 600 for securing the chip 110 to thecarrier substrate 130 via an edge double adhesive layer (made up ofadhesive layers 540 and 550), according to one embodiment. The baseadhesive layer 540 is deposited 602 onto the carrier substrate 130 usingstandard thin film deposition techniques, such as spin-coating anddip-coating.

The base adhesive layer 540 and the edge adhesive layer 550 are made ofadhesive materials with different properties such that they can beremoved separately. The example combinations of materials discussed withrespect to the double adhesive layer chip transfer system of FIGS. 1,2A, and 2B may also be used for the edge double adhesive layer chiptransfer system discussed here. Specifically, at least one of the baseand edge adhesive layers 540 and 550 is a polymer material, and, in someembodiments, the other of the base and edge adhesive layers 540 and 550is a wax, such as carnauba wax or bees wax. In one embodiment, the baseadhesive material comprises PVAc and the edge adhesive material is PVA.In another embodiment, the base adhesive material comprises PVP and theedge adhesive material is PVB. The thickness of the base adhesive layer540 controls the reduced adhesion strength of the edge double adhesivelayer system. Accordingly, the base adhesive layer 540 may be relativelythin to facilitate easy release of the chip 110. In one embodiment, thebase adhesive layer 540 is approximately 1 micrometer thick.

In one embodiment, the base adhesive layer 540 is separated into a firstbase adhesive layer and a second base adhesive layer. The first andsecond base adhesive layers may be similar to the first and secondadhesive layers 140 and 150 discussed in FIGS. 1, 2A, and 2B. They maybe made of different materials with different properties and may besoftened and/or removed independently.

The base adhesive layer 540 is dried 604, such as by evaporation, anelectron beam, UV radiation, heat, or chemical drying agents.

The carrier substrate 130 is heated 606 to soften the base adhesivelayer 540 in preparation for chip 110 placement 210. The temperaturerequired to soften the base adhesive layer 540 depends on the type ofadhesive material being used. Typically, the carrier substrate 130 isheated 606 at least to the glass transition temperatures of the baseadhesive layer 540. For example, if the base adhesive layer 540 is PVAc,the carrier substrate 130 is heated to at least 85° C. prior to chipplacement 210. Alternatively, when the base adhesive layer 540 is PVP,the carrier substrate 130 is heated to or past 110-180° C.

The chip 110 is weighted (e.g., with a few grams) and placed 608 on theheated carrier substrate 130, through the base adhesive layer 540. Insome embodiments, the base adhesive layer 540 is not dried 604, thecarrier substrate 130 is not heated 606, and the chip 110 is notweighted during placement 608.

After the chip 110 has been placed 608, the edge adhesive layer 550 isdeposited around the edges of the fabrication substrate 120 and cominginto contact of edges of the chip 110. In embodiments where multiplechips 110 are attached to the same fabrication substrate 120, the edgeadhesive layer 550 only comes into contact with the outermost edges ofthe multiple chips 110. That is, the edge adhesive layer 550 does notcome into contact with an edge of a chip 110 that is directly adjacentto an edge of another chip 110. The edge adhesive layer 550 may bedeposited using convention deposition techniques, or more targeteddeposition techniques, such as injection.

FIG. 6B is a flow chart of a method 650 for releasing a chip 110 that isattached to a carrier substrate 130 via an edge double adhesive layer(made up of adhesive layers 540 and 550), according to one embodiment.Method 650 includes optional processing steps (indicated in dottedlines) through which the fabrication substrate 120 can be removed. Theseare an example of what processing may require a stronger level ofadhesion. Alternatively or additionally, the carrier substrate 130 maybe used to secure the chip 110 for transport or shipping.

While the chip 110 is strongly adhered to the carrier substrate 130, thefabrication substrate 120 may be removed by performing 652 laserlift-off or a similar process to break any physical and/or chemicalbonds between the chip 110 and the fabrication substrate 120.

The level of adhesion between the chip 110 and the carrier substrate 130is decreased by removing 654 the edge adhesive layer 550 from thecarrier substrate 130 and the chip 110. The chip 110 remains secured tothe carrier substrate 130 via the base adhesive layer 540. In oneembodiment, the edge adhesive layer 550 is removed 654 by the rinsingthe carrier substrate 130 with a solvent in which the edge adhesivelayer 550 is soluble but the base adhesive layer 540 is not. Examplesolvents include water, butanone, ethanol, and isopropanol.Specifically, the carrier substrate 130 is rinsed with water if the edgeadhesive layer 550 is PVA (and the base adhesive layer 540 is not PVP),with butanone if the edge adhesive layer 550 is PVAc, with water (if thebase adhesive layer 540 is not PVA) or isopropanol if the edge adhesivelayer 550 is PVP, and the carrier substrate 130 is rinsed with ethanolif the base adhesive layer 550 is PVB.

After the edge adhesive layer 550 is removed 654, the fabricationsubstrate 120, however, is no longer attached to the chip 110 (viachemical/physical bonds or via the edge adhesive layer 550), so it canbe removed 656 from the chip 110. The fabrication substrate 120 may beheated to aid in its removal 656. For example, a sapphire fabricationsubstrate 120 is heated to 30° C. prior to removal 656.

In some embodiments, the removal 654 of the edge adhesive layer 550 andthe removal 656 of the fabrication substrate 120 can be combined.Specifically, the solvent used to remove 654 the edge adhesive layer 550is heated above 30° C. such that it simultaneously dissolves the edgeadhesive layer 550 and weakens the interface between the chip 110 andthe fabrication substrate 120 (e.g., by melting a gallium layer betweena gallium nitride chip 110 and a sapphire fabrication substrate 120after LLO). Accordingly, both the edge adhesive layer 550 and thefabrication substrate 120 are removed 654 and 656 after application ofthe heated solvent. Combining these steps may be advantageous tominimize the handling of the chips 110 and avoid extra precautions topreserve the quality of the chips 110 during these steps.

The carrier substrate 130 is heated 658 to soften the base adhesivelater 540 so that the chip 110 can be removed 660 from the carriersubstrate 130 (e.g., so it can be placed on a target substrate). Again,the temperature that the carrier substrate 130 is heated to depends onthe adhesive material being used. For example, the carrier substrate 130is heated to at least 45° C. when the base adhesive layer 540 is PVA, orto at least 110-180° C. when the base adhesive layer 540 is PVP.Alternatively or additionally, the base adhesive layer 540 can be dryetched to reduce its adhesion strength before removing 660 the chip 110from the carrier substrate 130.

ADDITIONAL CONSIDERATIONS

Upon reading this disclosure, those of skill in the art will appreciatestill additional alternative structural and functional designs for thedescribed embodiments as disclosed from the principles herein. Thus,while particular embodiments and applications have been illustrated anddescribed, it is to be understood that the disclosed embodiments are notlimited to the precise construction and components disclosed herein.Various modifications, changes and variations, which will be apparent tothose skilled in the art, may be made in the arrangement, operation anddetails of the method and apparatus disclosed herein without departingfrom the spirit and scope defined in the appended claims.

Finally, the language used in the specification has been principallyselected for readability and instructional purposes, and it may not havebeen selected to delineate or circumscribe the inventive subject matter.It is therefore intended that the scope of the invention be limited notby this detailed description, but rather by any claims that issue on anapplication based hereon. Accordingly, the disclosure of the embodimentsof the invention is intended to be illustrative, but not limiting, ofthe scope of the invention, which is set forth in the following claims.

What is claimed is:
 1. A method comprising: depositing a first adhesivelayer on a first substrate, the first adhesive layer comprises a firstmaterial; drying the first adhesive layer; providing a second substratewith one or more chips attached; placing the one or more chips on thefirst substrate through the first adhesive layer, the one or more chipsattached to the second substrate; depositing a second adhesive layer onthe first substrate, the second adhesive layer covering edges of thesecond substrate and an edge portion of at least one of the one or morechips, the second adhesive layer not covering other portions of the oneor more chips, the second adhesive layer made of a second material thatis different from the first material, at least one of the first andsecond materials being a polymer material; performing laser lift-off onan interface of the one or more chips and the second substrate; removingat least the portions of the second adhesive layer covering the edges ofthe second substrate after performing the laser lift-off; removing thesecond substrate from the one or more chips after performing the laserlift-off; softening the first adhesive layer after removing the secondsubstrate; and removing the one or more chips from the first substrate.2. The method of claim 1, wherein the one or more chips are weightedduring the placement.
 3. The method of claim 1, wherein the secondadhesive layer is deposited via injection.
 4. The method of claim 1,wherein softening the first adhesive layer comprises heating the firstsubstrate to at least a first glass transition temperature of the firstadhesive material.
 5. The method of claim 1, wherein removing the secondadhesive layer comprises dissolving the second adhesive layer in asolvent in which the second adhesive material is soluble, the firstadhesive material not being soluble in the solvent.
 6. The method ofclaim 5, wherein the solvent is water.
 7. The method of claim 1, whereinthe first adhesive material is polyvinyl acetate, and the secondadhesive material is polyvinyl alcohol.
 8. The method of claim 1,wherein the first adhesive material is polyvinyl pyrrolidone, and thesecond adhesive material is polyvinyl butyral.
 9. The method of claim 1,wherein the first substrate is made of is a hard material.
 10. Themethod of claim 9, wherein the first substrate is made of glass.
 11. Themethod of claim 1, wherein the second substrate is made of sapphire. 12.The method of claim 1, wherein the first adhesive layer is approximately1 micrometer thick.
 13. A method comprising: securing one or more chipsto a first substrate by: depositing a first adhesive layer on the firstsubstrate, the first adhesive layer comprising a first material;providing a second substrate with one or more chips attached; placingone or more chips on the first substrate through the first adhesivelayer, the one or more chips attached to the second substrate; anddepositing a second adhesive layer on the first substrate, the secondadhesive layer covering edges of the second substrate and an edgeportion of at least one of the one or more chips, the second adhesivelayer not covering other portions of the one or more chips, the secondadhesive layer made of a second material that is different from thefirst material, at least one of the first and second materials being apolymer material; and detaching the one or more chips from the firstsubstrate by: removing the second adhesive layer from the firstsubstrate; softening the first adhesive layer after removing the secondadhesive layer; and removing the one or more chips from the firstsubstrate after softening the first adhesive layer.
 14. The method ofclaim 13, further comprising: transporting the one or more chips whilethe one or more chips are secured to the first substrate.
 15. The methodof claim 13, further comprising: performing one or more fabricationsteps on the one or more chips while secured to the first substrate. 16.The method of claim 13, wherein the second adhesive layer is depositedvia injection.
 17. The method of claim 13, wherein removing the secondadhesive layer comprises dissolving the second adhesive layer in asolvent in which the second adhesive material is soluble, the firstadhesive material not being soluble in the solvent.
 18. The method ofclaim 13, wherein the first material and the second material aredifferent materials each selected from a group consisting of polyvinylacetate, polyvinyl pyrrolidone, polyvinyl alcohol, and polyvinylbutyral.
 19. The method of claim 13, wherein the first adhesive layer isapproximately 1 micrometer thick.
 20. The method of claim 13, whereinone of the first material and the second material is a wax.